How To Tell If Filament Is Water Damaged: 4 Helpful Signs

3D printers are technological innovations that require filaments to create certain designs. It is important to learn how to tell if filament is water damaged so that you’ll be able to fix specific errors when it comes to the machine.


how to tell if filament is water damaged

What Are 3D Printer Filaments?

Filaments are the inks of a 3D printer. The filaments used in 3D printing are called thermoplastics – plastics that melt rather than burn during heating. Once melted, the material can be molded and will solidify during cooling.

Filaments come in spools weighing between 500 grams to 2 kilograms. In terms of thickness, a user can choose between 1.75 millimeters to 3 millimeters. These filaments are fed and melted in the heating chamber of the 3D printer and squirted through a nozzle to form the printed object.


Types Of Filaments

Filaments have different sensitivities to moisture, meaning each will require specific storage and operating conditions. The printed objects from each filament will also have varying properties, depending on the filaments’ characteristics. Below is an itemization of the most common filaments used in 3D printing:

  • ABS – Also known as acrylonitrile butadiene styrene, ABS produce tough, durable, and non-toxic materials like Legos.
  • PLA – Polylactic acid is plant-based, biodegradable, and is harder than ABS.
  • Nylon – Cheap, durable, and flexible, nylon melts at high temperatures of 240 degrees Celsius.
  • TPEs – Thermoplastic elastomers produce very flexible printed objects.
  • HIPS – High-impact polystyrene is similar to ABS but is soluble in limonene, a citrus-based solvent.
  • PVA – Polyvinyl alcohol is a water-soluble filament that can be used as supporting material in dual-extruder printers.

Nowadays, these filaments are combined with flakes or powders of other materials such as wood blends, sandstone, limestone, carbon fiber, iron, brass, aluminum, copper, and bronze. Although these composite filaments are more expensive, they adapt the properties of the added materials. For example, composite filaments made with carbon fiber offer increased strength but also cost higher.


Signs That A Filament Is Water Damaged

Filaments are hygroscopic in nature, which means they quickly absorb moisture. It is not easy to know if a filament absorbed too much water just by looking at the spool. The best way to tell if moisture absorption occurred is to test the filaments in the 3D printer and observe for the following signs.


1. Popping sounds during extrusion

The cracking or popping sounds during extrusion are caused by the quick boiling of the excess moisture. The temperature of the printed head is significantly higher than the boiling point of water, causing the moisture to pop out of the molten filament as bubbles.


2. Steam, oozing, or stringing from the extruder

These symptoms occur severely when the filament used is wet. It is also possible that the filament continues to flow even after turning off the extrusion operation.


3. Extruder jams

The water absorbed by the filaments makes its way in between the building blocks of the polymer. These building blocks are called monomers, and spaces are vacated by water in between these units during heating. The filaments then turn into a paste that may clog the extruder or the nozzle.


4. Poor quality prints

As mentioned in the previous paragraph, moisture creeps between the filaments’ individual units, affecting their durability. The resulting printed object will have reduced tensile strength and may snap easily. Other effects of moisture absorption in filaments are the presence of fuzzy/rough surfaces and poor adhesion of the print.


How To Dry A Water Damaged Filament

There are three primary ways to dry a water damaged filament, namely:


1. Filament dryers

This equipment is specifically designed for drying wet filaments. Various dryers have different methods of drying, but the principle remains the same.

To operate, the spools are put inside the dryer, the setting is adjusted, and the dried filament is ready after a  predetermined time. Some filament dryers can also be installed with the 3D printer, allowing simultaneous drying and printing from the dried filament.


2. Ovens

Ovens are reliable appliances whether in cooking or drying something. For wet filaments, throw the spool inside the preheated oven, and wait for 4 to 6 hours.

The drying temperature depends on the filament material. The common ones are set at 40 to 45 degrees Celsius (PLA) or about 80 degrees Celsius for ABS and nylon.


3. Food dehydrators

If your oven cannot maintain a target temperature, you may use a food dehydrator instead. Food dehydrators operate at a lower temperature than ovens, so use the highest temperature setting when drying ABS and nylon when 80 degrees Celsius is not attainable.

Unlike in electronics, the use of a hair dryer to dry wet filaments is not advisable. This technique will only dry the surfaces but not the inside of the spool.

Once you are done drying the filament, you may resume printing. There are instances where the printed objects must be removed from the printing bed. In these cases, there are tips available online to help you with this scenario.

You do not want your dried filaments to get wet again, don’t you? So, store them in humidity-controlled environments such as airtight boxes with desiccant packs.



The best way on how to tell if filament is water damaged is by running it through your 3D printer. The resulting product will manifest moisture absorption, and you will know what to do from there.

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